add ubuntu 21.10 to ci (#4446)

* add ubuntu 21.10 to ci

remove ubuntu 20.10

* forgot to update dockerfile

* add googletest from repos

* update downloaded gtest

ideally this should just grab the master version

* fix hash

* fix cmake issue

.ci/UbuntuImpish/Dockerfile

@@ -0,0 +1,24 @@
+FROM ubuntu:impish
+
+RUN apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+        build-essential \
+        ccache \
+        clang-format \
+        cmake \
+        file \
+        g++ \
+        git \
+        liblzma-dev \
+        libmariadb-dev-compat \
+        libprotobuf-dev \
+        libqt5multimedia5-plugins \
+        libqt5sql5-mysql \
+        libqt5svg5-dev \
+        libqt5websockets5-dev \
+        protobuf-compiler \
+        qtmultimedia5-dev \
+        qttools5-dev \
+        qttools5-dev-tools \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*